Purpose: This study aimed to evaluate the effectiveness of the National HPV Vaccination Program of South Korea among its entire female population, particularly among younger age groups.
Materials and methods: We first predicted the incidence of cervical cancer over the next 20 years (2021-2040) using the Nordpred package based on Møller's age-period-cohort model under several scenarios for the National HPV Vaccination Program. We calculated the potential impact fractions (PIFs) and proportional differences under the current national vaccination programs, and alternative scenarios using the no-vaccination assumption as a reference.
Results: We estimated that the current national vaccination program would prevent 4.13% of cervical cancer cases and reduce the age-standardized incidence rate (ASR) by 8.79% in the overall population by 2036-2040. Under the alternative scenario of implementing the nine-valent vaccine, 5.13% of cervical cancer cases could be prevented and the ASR reduced by 10.93% during the same period. In another scenario, expanding the vaccination age to 9-17 years could prevent 10.19% of cervical cancer cases, with the ASR reduced by 18.57% during the same period. When restricted to ages <40 years, the prevention effect was remarkably greater. We predict that the current national HPV program will reduce its incidence by more than 30% between 2036 and 2040 in women aged <40 years.
Conclusion: The effectiveness of the vaccination program in reducing the incidence of cervical cancer was confirmed, with a considerable impact anticipated in younger age groups.
Keywords: Human Papillomavirus Viruses; Papillomavirus Vaccines; Potential Impact Fraction; Uterine Cervical Neoplasms.